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Catalyst Drivers force 4:2:2 chroma

Question asked by li7in6 on Jul 21, 2016
Latest reply on Jan 6, 2017 by mdalton10

I have a UN55JS7000 4k@60hz with 4:4:4 chroma capable display hooked up through HDMI to a Club3d miniDP 1.2 to HDMI 2.0 active adapter. This is all plugged into the mini DisplayPort on a Radeon HD 7850.


If I uninstall all AMD drivers and Catalyst software then reboot, the computer will detect the display and automatically put out 3840x2160 @60hz. The display will pass all 4:4:4 chroma tests with flying colors. The chroma test images being used are both the pink "4:2:2/4:4:4" test image as well as the "Quick brown fox" test image, both are properly unscaled when I test for chroma. This is important because it demonstrates that this hardware setup is capable of displaying a 4k 4:4:4 chroma image with this hardware setup so long as the MAD drivers are not installed.


Now my big issue is that as soon as I install the AMD drivers and Catalyst software the display will blank out and back in, and begin displaying 4:2:2 chroma.

Hunting through the settings there is no "pixel format" on the "Radeon Additional Settings" under "My Digital Flat-Panels" as there was with my monitor to allow me to select the color space and subsampling setup.


Essentially when I install my video card's drivers I am locked into an inferior 4:2:2 chroma subsampling setting with no option to change it. Without the drivers and AMD software installed the display will default to the correct 4:4:4 chroma output and everything is fine... except I'm not running the correct drivers for my GPU.


Is this a bug with the Catalyst software and if so is it known and are there efforts being made to fix it?


Is there a way to enable to "Pixel Format" options normally available for this display ro find out why these options are gone?


I have tried uninstalling and reinstalling different versions of the AMD software/driver suit with the same results over and over. I have tried different HDMI cables and different Mini DP ports and different HDMI ports. The UHD color setting IS enabled on the display to enable it to output a 4:4:4 chroma image.


Again the display outputs the correct 4:4:4 chroma 4k image as long as no AMD drivers are installed. As soon as AMD drivers are installed the display will only put out 4:2:2 chroma and there is no option to change chroma subsampling or RBG/YCbCr settings for this display.